Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity.
In use, the electrode catheter is inserted into a major vein or artery, e.g., femoral artery, and then guided into the chamber of the heart which is of concern. Within the heart, the ability to control the exact position and orientation of the catheter tip is critical and largely determines how useful the catheter is.
Steerable catheters are generally well-known. For example, U.S. Patent No. RE 34,502 describes a catheter having a control handle comprising a housing having a piston chamber at its distal end. A piston is mounted in the piston chamber and is afforded lengthwise movement. The proximal end of the catheter body is attached to the piston. A puller wire is attached to the housing and extends through the piston and through the catheter body. The distal end of the puller wire is anchored in the tip section of the catheter. In this arrangement, lengthwise movement of the piston relative to the housing results in deflection of the distal end of the catheter body. The design described in RE 34,502 is generally limited to a catheter having a single puller wire.
Some catheter designs require more than one puller wire. For example, if a bidirectional catheter is desired, i.e., a catheter that can be deflected in more than one direction without rotating the catheter body, more than one puller wire becomes necessary. Catheters having two or more puller wires and handles for controlling the multiple puller wires are disclosed, for example, in U.S. Pat. Nos. 6,171,277 and 6,183,463. However, these patents describe catheter handles whereby simultaneous proximal movement of the puller wires relative to the catheter body is prohibited, which is desirable for certain applications. However, for other applications, it is desirable to simultaneously move the puller wires proximally relative to the catheter body.